In general, testing has been carried out in order to secure the safety of passengers in the event of an automobile crash, which is an important factor in ensuring the stability of an automobile. In various countries, safety standards in the event of such crashes are regulated and may be itemized, including import restrictions.
For example, the Insurance Institute for Highway Safety (IIHS) has conducted a frontal crash performance test and a small overlap frontal crash performance test, an overlap crash test in the case of a crash involving 25% of a front portion of a vehicle.
In the meantime, as illustrated in FIG. 1, in the case of pick-up trucks having a linear frame, a front side frame 1 in a portion in which an engine is mounted is formed of a single material having a non-linear shape.
Such a frontal crash performance test of pick-up trucks has been developed to set frontal crash performance indices in such a manner that the time to zero velocity (TTZV) is 70 ms or more, the maximum deceleration rate is about 40 G, where 1 G is 9.8 m/s2, and the effective deceleration rate is 30 G or less, until the speed of a pick-up truck reaches 0 after crashing into a steel wall.
The results of a frontal crash performance test, illustrated in FIG. 2, represent a TTZV of 91.1 ms, a maximum deceleration rate of 33.2 G, and an effective deceleration rate of 19.6 G.
In other words, in the frontal crash performance test illustrated in FIG. 2, transformation may not substantially occur in a rear portion of the front side frame 1 in which an engine is mounted. Bending transformation may only occur in a first bent portion 31 and a second bent portion 32 of a bent portion 30 having a bent form, formed in the front side frame 1, thereby satisfying target performance by absorbing energy.
However, the results of a small overlap frontal crash performance test illustrated in FIG. 3 may not satisfy target performance. It can be confirmed in FIG. 4 that excessive transformation of a passenger cabin on which a passenger rides occurs.
Thus, research into an automotive front side frame, satisfying an entirety of the frontal crash performance test and the small overlap frontal crash test, described above, is required.